AN economist known for his negative economic predictions has called a price crash on bitcoin as authorities clamp down on the cryptocurrency.

Nouriel Roubini, also known as Dr Doom has predicted bitcoin will hit zero

Nouriel Roubini, professor of economics at Stern School, part of the New York University, also known as Dr Doom, has now predicted bitcoin will hit zero.

The chairman of Roubini Macro Associates took to Twitter to share his forecast as Christopher Giancarlo, chairman of the Commodity Futures Trading Commission (CFTC), and Jay Clayton, chairman of the Securities and Exchange Commission (SEC) appeared at a Congressional hearing on cryptocurrencies.

And Mr Roubini warned investors to "HODL" or "hold on for dear life" - a phrase popular in online forums after someone spelt 'hold' wrong. It is often used for people holding rather than selling in the cryptocurrency market during times of extreme volatility.

"And the US Congressional Hearing on Crypto-Scams is still a day away. HODL nuts will hold their melting bitcoins all the way down to ZERO while scammers and whales dump and run.”

Dr Doom goes onto describe the techniques certain traders use to push up prices. one term used is ‘wash’. This is where someone in the crypto world buys and sells their own order to manipulate the market.

Fears have arisen that such techniques could take place on bitcoin exchanges.

He added: “As bitcoin crashes to a $5K handle the wash traders move rapidly into action to prop it up...price and quantity action now clearly consistent with criminal wash trades...will the SEC and CFTC start looking into these criminal activities?”

Last week Mr Roubini told Bloomberg that bitcoin is the “biggest bubble in human history.”

Bitcoin is currently valued at $7,348, ethereum sits at $749 and Ripple lies at $0.73.

Bitcoin briefly slid below $6,000 on Tuesday to its lowest point so far this year in a sell-off that has seen the cryptocurrency lose more than half its value.

Bitcoin has fallen heavily in recent sessions as a risk-off mood across markets, worries about a regulatory clampdown, and moves by banks to ban buying bitcoin on credit cards have rattled investors, pushing prices lower.

The virtual currency hit a peak of almost $20,000 in December, receding to around $13,800 at the start of the new year.

On the Luxembourg-based Bitstamp exchange, bitcoin fell to as low as $5,920, its weakest since mid-November, before recovering back above $6,000. It was trading at $6,860 by 1315 GMT, almost flat on the day.

Other cryptocurrencies have also dropped sharply in value this week. Ethereum, the second-largest by market value, is down almost 11 percent over the past 24 hours, while the third-largest, Ripple, is down 7 percent, according to trade website Coinmarketcap.com. Bitcoin is down more than 10 percent in that period.